The present invention relates generally to the field of waste disposal, and, more specifically, to the encapsulation and isolation of nuclear materials, including waste products, inside fullerenes. The invention is a result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).
The disposal of nuclear materials, particularly nuclear waste materials created from sources such as nuclear power production, nuclear weapon programs, and medicine has plagued the nuclear power industry, as well as the scientific community, for decades. The facts that erected low level disposal sites have not opened, and that the current political climate does not favor the installation of new sites, indicate that the prospect for safe and adequate nuclear waste disposal in the near future is dim. This lack of disposal facilities will limit the future of nuclear power production at a time when a lowering of emissions from fossil fuel plants is needed.
With some nuclear isotopes having half lives of thousands of years, the need to provide especially stable storage facilities is clearly shown. However, natural features, such as ground water levels, soil characteristics and earthquake potential, make finding a suitable site extremely difficult, even when disregarding the political problems.
Examples of the problems involved with disposal is illustrated by the problems with the opening of the Waste Isolation Pilot Plant in New Mexico, and with the opposition mounted to development of the Yucca Mountain project in Nevada. With the increasing realization of the long term required for storage, and of the need to prevent escape of waste products into water supplies, renders the need for alternative safe disposal methods of paramount importance.
Recently, researchers have discovered a new form of carbon molecules known as "fullerenes." This discovery has sparked the interest of a large segment of the scientific community, and has led to the conception of numerous practical applications for the molecules. Some of the better known fullerenes include C.sub.60 (buckminsterfullerene) which has icosohedral symmetry, consisting of 12 five-membered rings and 20 six-membered rings, resembling the patchwork faces of a soccer ball; the ellipsoidally shaped C.sub.70, and C.sub.84 ; and the giant, spherically shaped C.sub.256.
Studies of fullerenes have indicated that this material exhibits a remarkable range of physical and chemical properties. For example, various metal ions have been encapsulated within a fullerene cage. Also, fullerenes have been shown to have low density and unusually high thermal and mechanical stability, and have been generated with metals to form materials in which the metal ions are positioned inside the hollow fullerene cage.
With the current state of concern over the proper storage of nuclear materials, it would be of immeasurable benefit to be able to encapsulate such waste inside a stable molecule. Previous attempts at such binding have involved encapsulation within glasses, ceramics, or cements. In this encapsulation technology, each metal ion or cluster of ions is surrounded by relatively few matrix atoms. Additionally, the stability of such glasses is affected by the encapsulated material.
Because of radiation damage caused by the decay process, materials produced using the above methods suffer progressive degradation of the matrix molecular structure, allowing for the slow release of decay products, as well as the leaching of the parent isotope into the environment. This is not the case with fullerenes.
The remarkable stability of the fullerene cages will allow them to withstand the nuclear decay processes without severe degradation, assuring that the nuclear products will remain immobilized. Additionally, the fullerene molecules exhibit self-healing properties, meaning that in the event of a rupture, the partially broken cage will reclose. It is also likely that the synthesis of fullerene encapsulated metals can be carried out efficiently on a large scale, making the process attractive for nuclear waste disposal and storage. These features have led to the present invention, in which radioactive wastes are encapsulated within the fullerene molecule.
It is therefore an object of the present invention to provide a secure means for storage of radioactive materials.
It is another object of the present invention to provide a method for storing radioactive waste materials.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the present invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.